Related Clues:

• ___ Heels (college team)
• Smoker's residue
• One unhealthy part of cigarettes
• Goo in a prehistoric pit
• Seafarer, informally
• Paving substance
• Sticky substance used in road construction
• Car washer's challenge
• Source of some fossils
• Roadwork gunk
• Car wash challenge
• Alternative to gravel, perhaps
• Pitch relative
• Therapeutic shampoo additive
• Roofer's remedy